Last summer, the vacuum hose to activate the auto hubs developed a leak. I can lock the hubs, but when I switch to 4wd, that leak kicks the heater to defrost, so my head is roasting while my feet are freezing. This is getting annoying.

Can anyone point me to where the leak usually develops? I had a quick look yesterday, and didn't see anything obviously wrong.

Inside the knuckle where the stub axle goes through, there is a seal (2 pc.) if it leaks then you will have a vacuum leak. Also, the hoses could have a crack in them somewhere. The seals are dealer only and cost about $80 per side I think.

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